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Really cheap true cc/cv usb charging board

Hello everybody!

I'm a new member in this community. I always liked flashlights but i was unaware that there were people addicted to them.

I have a cheap 3xAAA flashlight that i modded with an R2 drop in. I use it all the time in my work (i'm a mechanical engineer and i work in a brick producing plant). The main feature is an adjustable magnetic base that allows me to attach it to any machine and point it anywhere.

At this point i want to upgrade to something more bright, more reliable and with longer runtime, but i want to do it on a tight budget.

I'm thinking of buying the ultrafire 501-B flashlight with the XM-L T6. I can get it for 14 USD in ebay.

What made me open this thread was the charger. After googling a while, i'm convinced that i can have a very good charger for a very low price. I don't need a fancy cradle charger, or multi bay charger, just something that i can attach to a 18650 and charge it saflely acording to the cc/cv algorithm.

I was going around the TP4054 IC, when i found this board:

Ebay Item number: 330699360128

It uses a TP4056 IC, has 1A output current, but can be adjusted to other currents by changing one resistor. It follows cc/cv algorithm. If i can charge a 18650 battery with a 1A current then this is pretty much plug and play.

This leads me to my first question. Is it safe to charge a 18650 battery, let's say a 2500mAh with 1A current?

On the other hand, if i connect this to an USB port (maximum output of 500mA) or a wall cell phone charger (also 500mA), then, even with this resistor setting, the current going to the battery will allways be lower than 500mA, right?

Another issue is the battery temperature. On this board the monitoring of the battery temperature is disabled. I believe thats also true for the majority of the chargers out there, but still i have safety concerns. So i had an idea,and i would like to know your opinion. This chip as a built in thermal feedback, that regulates the charging current to prevent the die from overheating. I was thinking that if i place the battery on top of the chip while charging, and if by any reason it overheats then it will also heat the chip reducing the charging current. Will this work? Any of you guys have experience with this board or IC?

Previously i was thinking of modding the flashlight so that the battery could be charged inside, but i'm not so sure now. Is it safe to charge the battery in a so tight sealed enviroment?

This thread is mainly about the charger but please fell free to give me your opinion about the flashlight also.

Re: Really cheap true cc/cv usb charging board

Originally Posted by litos

This leads me to my first question. Is it safe to charge a 18650 battery, let's say a 2500mAh with 1A current?

Yes

On the other hand, if i connect this to an USB port (maximum output of 500mA) or a wall cell phone charger (also 500mA), then, even with this resistor setting, the current going to the battery will allways be lower than 500mA, right?

Yes

Another issue is the battery temperature. On this board the monitoring of the battery temperature is disabled. I believe thats also true for the majority of the chargers out there, but still i have safety concerns. So i had an idea,and i would like to know your opinion. This chip as a built in thermal feedback, that regulates the charging current to prevent the die from overheating. I was thinking that if i place the battery on top of the chip while charging, and if by any reason it overheats then it will also heat the chip reducing the charging current. Will this work? Any of you guys have experience with this board or IC?

I have no idea. I guess so. At 500mA, you'd need a really dodgy 18650 to be worrying about overheating. Buy quality cells and you won't have much to worry about.

Previously i was thinking of modding the flashlight so that the battery could be charged inside, but i'm not so sure now. Is it safe to charge the battery in a so tight sealed enviroment?

If the battery vents while charging, your sealed environment would be more like a pipe bomb. If you don't want your light to be waterproof, you can drill a venting hole in it to allow for safe charging.

Re: Really cheap true cc/cv usb charging board

Hmmm... Seems like a perfect board to use for my bluetooth headset, so I don't have to carry 2 chargers with me all the time (its charger charges at 200 mA, while my cell phone charger charges at 1A, and my external battery pack charges at 600mA). Swap the input connector with a micro USB, put a micro USB output, change the resistor, and voila, 1 less charger I have to carry.

Now if I could find a 1.5v boost charger for charging at a constant 4.5/5v (lower current output, like 20mA would be fine, considering I usually charge my headset when I'm sleeping, and would also work great for my Ipod nano), I'd be ecstatic!

I have soooo many AAA, AA, and D cell batteries that could benefit from a charger like that, considering I don't go through many batteries in my E01 (same battery for the last 6-8 months), or my E05 (still on its first battery, after about 2-3 weeks).

Re: Really cheap true cc/cv usb charging board

Originally Posted by litos

On the other hand, if i connect this to an USB port (maximum output of 500mA) or a wall cell phone charger (also 500mA), then, even with this resistor setting, the current going to the battery will allways be lower than 500mA, right?

You will have to lower the charge current to <500mA to be compatible, it wont limit current, other than to just shut off the port/trip a polyfuse.

Re: Really cheap true cc/cv usb charging board

Has anyone received any of these charger boards yet?

I have just received three, (yet to test them) I was interest in varying the current as stated in the auction, I'm unsure of the resistor to change. Three message to the seller so far no helpful reply one stating "change the resistor" but not tell me which resistor, one saying "it can't be done" which is wrong I'm sure and the final message asking if I want a refund.

I'll post progress if any, currently waiting on a fourth reply but I'm not holding my breath for a sensible response.

Re: Really cheap true cc/cv usb charging board

Originally Posted by Norm

Has anyone received any of these charger boards yet?

I have just received three, (yet to test them) I was interest in varying the current as stated in the auction, I'm unsure of the resistor to change. Three message to the seller so far no helpful reply one stating "change the resistor" but not tell me which resistor, one saying "it can't be done" which is wrong I'm sure and the final message asking if I want a refund.

I'll post progress if any, currently waiting on a fourth reply but I'm not holding my breath for a sensible response.

Norm

I received one yesterday. I myself have had no time to play either. Just checked the datasheet for the TP4056 IC it uses and have come to the conclusion what you are looking for is in the following pic.

Re: Really cheap true cc/cv usb charging board

Originally Posted by AmperSand

I received one yesterday. I myself have had no time to play either. Just checked the datasheet for the TP4056 IC it uses and have come to the conclusion what you are looking for is in the following pic.

Sorry the pic looks a bit dodgy, iPhone at work wasn't exactly a great shot but gets the idea across.
If my soldering iron and other gear hadn't been stolen from my car a few months ago I'd have had mine nice and functional as a charger for my 3100mah cells I use in my Fenix PD31/Eagletac D25LC2/Eagletac G25C2. Normally use a hobby charger at home. But this is great for laptop bag/at work without having to take a hobby charger everywhere.
Thinking about getting some 18650 holders and building the USB module into it.
Portable/safe Li-ion charger!!!!

Re: Really cheap true cc/cv usb charging board

Just quickly rigged mine up to charge an 18650 with magnet connectors. I'm at work so I can't leave it complete at the moment but so far its gone from 4.05v (cell I have in my EDC) and its currently still in constant current stage and is upto 4.15v. Have a multimeter connected to see voltage on output to battery so I can monitor it. Its only going to my computer USB port, so its probably limited to around 500mA.
Everything seems to be going ok. I might solder the leads I have with aligator clips (which I will use magnets with) to the board and use some clear heatshrink on the board and I think that may be good enough for portability, keeps the size small.

All in all seems to be going quite well. Should be good to be able to top up my EDC's cell while sitting at my desk without having to lug around too much gear at all. Bargain for the price.

Re: Really cheap true cc/cv usb charging board

The basic problem of this board is IMO if you are using this charger board on a USB port @1A you may destroy the power lines of the used USB power port. In general most USB ports are only capable driving 500mA as maximum current. There are on some devices "high power ports" but this is not specified in USB 2.0. Depending on the design of the USB power generation of the PC it may happen the fuse of the USB power line will be destroyed or the port electronics.

Re: Really cheap true cc/cv usb charging board

Just picked up a few of these as tinker boards, look like great fun little projects and great EDC backup chargers.

One question I know I'll have is how to determine the value of the resister to change? I was thinking I might even solder in a second breadboard with a multi-position switch... but really I'm a "hack" when it comes to this stuff (I still like to play at tho!!!) and don't know how to determine that resister value... any help there would be fantastic!

The basic problem of this board is IMO if you are using this charger board on a USB port @1A you may destroy the power lines of the used USB power port. In general most USB ports are only capable driving 500mA as maximum current. There are on some devices "high power ports" but this is not specified in USB 2.0. Depending on the design of the USB power generation of the PC it may happen the fuse of the USB power line will be destroyed or the port electronics.

It's not that it will 'suck' 1A from a 500mA port... It'll just deliver 500 mA to the battery.

Re: Really cheap true cc/cv usb charging board

It's not that it will 'suck' 1A from a 500mA port... It'll just deliver 500 mA to the battery.

I doubt there'd be any risk to a USB port.

+1, there should likely be no risk to the port in 99.9% of the computers.

IIRC some older designed ports (we're going back a few years here) would shut off entirely if it detected a current draw higher than it wanted to give (and 500ma was being optimistic for some of those older ports). Sometimes power cycling the computer was needed to reset the protection, sometimes just removing the load and waiting 20 secs would do it. bottom line, no damage to anything, worst case, no charge in the battery.

Modern ports will typically just deliver the 500ma and give the charger the finger on the other half. Some will give more than 500ma

USB 3.0 ports are spec'ed to 900ma, but will probably give it the full 1a.

In action and charging! Just made up some alligator clip leads and soldered them to the board and encased the board in clear heatshrink.
Multimeter in line monitoring voltage for now.
Going to order a few more for use with battery cradles and maybe voltage display. Adding a switch to change charge modes as mentioned previously would also be good! Cheap and effective.

Follow up: the charger cooled down significantly as the cells voltage increased. I started the charge with the cells at 3.7V, so the charger was having to work harder to bring the input voltage down to the required charge voltage. Once the cells were at 4.0 - 4.1V the resistor was barely warm to the touch.

Re: Really cheap true cc/cv usb charging board

Nice looking little rig there mvyrmnd
I've got a cheap Chinese universal charger which is just begging to be gutted and replaced with an IC I can actually trust without keeping one hand firmly gripped on the fire extinguisher.

Ran across a few more models on the bay of e's today:

Item # 270958278638 - 1a rated, same TP4056 IC, no USB port wired in, no LED wired in. Board is a slightly different size. Twice the $$ ... looks like it would be good for a DIY integration project, not so good for plug-n-play.

Item # 160782678020 - 1.5a rated, 5.8-6v (but recommends 6v), almost the same board design as the one mentioned above, except this time its running TWO TP4056 IC's (still one output) and what looks like dual 1.6k resistors. Item description however is identical to much of the info from the original board, and doesn't seem to apply correctly to the new dual IC 1.5a designed board. going by the resistor tables, 1.6k would = ~750ma on a single IC, so it stands to reason that one each would = ~1.5a .... I don't know, anyone have thoughts on this one? Double the price at $6.... but tempting to get one to play around with.
Item # 150795982222 from the same seller provides a much better detailed and clear picture of the board components.

Item # 120898714536 - full size USB plug on it, board size looks to be quite about smaller.... but the picture is too small to see what kind of IC its using or any of its circuit designs... sold in pairs for $12 after shipping, so kind of an expensive experiment :/

Last edited by spectrrr; 04-21-2012 at 08:59 PM.
Reason: added one more item